1. Field of the Invention
The present invention relates, in general, to power distribution and distribution systems, and more particularly, to a modular power distribution unit for use in distributing power within the limited space of an equipment cabinet or rack, such as a computer equipment rack or a data storage cabinet.
2. Relevant Background
In the computer industry, mass storage systems and other computer systems typically include numerous multi-shelf cabinets or racks each holding multiple devices or enclosures, such as servers, disk drives, and other computer devices. These racks or rack systems are ideal for modular projects and are designed to accept standard sized devices having relatively standard power requirements and communication connections. Generally, the outer case includes an aluminum or steel framework fitted with covers and a series of connectors at the rear from which the devices or modules derive their power and exchange communication signals. The individual modules include a supporting chassis or housing that slides into the rack and is supported on guides, such as clip-in glides. Racks and rack systems are inherently flexible but are often expensive which drives users and rack manufacturers to efficiently use space within the rack or cabinet.
Each rack or cabinet typically only has a limited amount of space that is defined by or arranged into shelves. The shelves or shelf locations are configured to allow a device enclosure or module or other components to be plugged into and supported within the rack. Typical rack configurations call for 14 shelves although more shelves may be provided such as up to 24 or more shelves. If shelves are arranged vertically, a typical cabinet may have 14, 24, 32, or some other number of shelves that each occupy a certain amount of rack space, such as 3 retma (U) which is a standard mounting unit increment.
In practice, such as data centers, data storage, and the like, the racks are often densely packed with devices, such as servers, each requiring a primary power supply and a backup power supply for redundancy. For example, one arrangement uses up to 14-3U server enclosures in a rack requiring up to 28-750 watt power supplies. In another rack configuration, 21-2U servers are installed in a rack with 42-500 watt primary and redundant power supplies. A major challenge facing rack and equipment designers is how best to serve dense equipment users so as to provide increased power distribution while efficiently using the space within the rack to reduce cable clutter and connection and supply confusion. In other words, it is desirable to reduce the amount of space required for power distribution units (PDUs) (e.g., typically, a plurality of electrical receptacles to which electrical plugs of power cords can be connected and which are supplied by an inlet A/C power source) and power cords from the PDUs to the devices on the rack shelves to thereby free up rack U-space for more modules or enclosures.
Existing forms of power distribution require large volumes of cabinet or rack space as numerous PDUs are provided and often mounted in the rack that reduces the available shelves or U-space for computer or other desired components. For example, current PDU support requirements often call for as many as four to six 24 amp PDUs per rack, which leads to some rack configurations being limited when a maximum number of PDUs have been installed in the rack. In addition to the space required for the PDUs, large volumes of rack space may be required for the large number of power cords and other devices required to connect the PDUs to the individual devices or loads on the shelves. Often, an enclosure or device is located on a shelf which is relatively distant from the closest PDU which requires a long power cord to be snaked through the rack to the enclosure or device. The number of the cables and PDUs increases deployment complexity and can cause connection problems and mistakes. Additionally, after installation is completed, later expansions or modifications to the rack and power distribution arrangements are difficult to successfully implement.
Hence, there remains a need for an improved method and system for distributing power within an equipment rack or cabinet that requires less U-space, reduces the number and lengths and cost of connecting power supply cords used in racks (i.e., provides improved cable or cord management), is simple to customize, to install, and upgrade or later modify, and reduces the total deployment cost.
The present invention addresses the above discussed and additional problems by providing a modular power distribution system for use in distributing power to devices, modules, and/or enclosures mounted within equipment racks or cabinets. The power distribution system includes two basic building blocks: a core or control unit and one or more (and, typically 2 or 4) extension sticks or bars. The modular architecture allows a rack designer to custom configure a rack power distribution system based on their particular computer or other equipment needs and power availability, which minimizes cable clutter and confusion and increases available rack space.
Generally, the modular power distribution system concentrates central features of typical power distribution systems (e.g., a main power switch, circuit breakers, load groups, and power-on indication) into the core unit that is configured to be mounted at a remote location within the rack or cabinet enclosure. The housing of the core unit is thin, such as 1U or less, and includes clips or brackets for mounting vertically on a side of the rack (e.g., a 0U mounting) or horizontally (e.g., a 1U or less mounting). The extension bars include a number (e.g., 1 to 8 connections are provided in some embodiments) of AC power outlets, receptacles, connectors, cord segments, or other devices for connecting enclosures, modules, or devices in the rack to a power source. The extension bars include clips or other fasteners for mounting onto one corner support of the rack, which avoids using rack U-space for the extension bars while also enabling positioning of the bars at nearly any height within the rack and typically, near the rack positions or shelves of the devices being powered to reduce the need for long lengths of power supply cords and extend outlets along the entire or any desired portion of the length of the rack.
In operation, the core unit provides protected outputs that feed power to multiple high current outlets in the extension bars that can be used for connecting the high current loads, e.g., the enclosures, modules, or devices mounted on the shelves of the rack, to an acceptable power supply or source. The extension bars each connect directly to the core unit via a flexible power supply cord. The extension bars effectively locate the xe2x80x9cfanning outxe2x80x9d of the AC power in the rack closer to the loads and eliminates many power supply cords that were required in previous distribution arrangements. A wide range of capacities may be provided according to the invention (such as 16 to 40 amps devices) and numerous outlets may be provided in each modular power distribution system, such as 32 outlets with the used of 4 extension bars each having 8 AC power outlets (which in turn may be any of several industry standard connector families or be short power leads that connect directly to the load when it is desired to eliminate power cords).
More particularly, a power distribution system is provided for distributing power to electrical or computer equipment in an equipment rack. The system includes a control unit mounted within the rack having a power input electrically connected to a power source (such as with a cable or hardwired to an AC power source or facility source) and a converter for converting the input power from the source to a power supply required by the rack equipment. The control unit includes a housing on which a plurality of power outlets or connections are mounted for providing an electrical connection to the control unit and for distributing the converted power supply to the equipment. An extension bar is mounted within the rack typically adjacent one of the corner supports of the rack. The extension bar includes a power inlet and is connected via an electrical conductor or power cord to one of the power outlets of the control unit. The extension bar includes a number of power outlets (such as up to or more than 8) adapted for electrical connection to power supply lines (cords or hardwiring) from the rack equipment. The control unit housing typically includes one or more brackets for rigidly mounting the housing to the corner supports of the rack. In some embodiments, the control unit is mounted vertically in a 0U mounting with the thin (i.e., less than about 1U) cross-section of the housing positioned between two adjacent corner supports. In other embodiments, the control unit is mounted horizontally in a less than 1U mounting with the thin cross-section of the house position horizontally between the corner supports.